1. Field of the Invention
This invention relates to a forced air heater, and more particularly to a forced air heater of the direct gas-fired, portable type which draws heated air produced by a removable burner module in a combustion chamber into a forced air blower and then exhausts the heated air into the space to be heated.
2. Description of the Prior Art
Numerous types of gas-fired forced air heaters have been developed and are known in the art. The most common type is typically tubular in shape, wherein a motor-driven fan pushes air through a burner combustion chamber and out of a heater exit, as disclosed in the U.S. Pat. No. 4,244,349 issued to W. W. Velie on Jan. 13, 1981. A less common type is of a box-shaped configuration, rather than tubular, wherein air is pulled, rather than pushed, through the combustion chamber. These latter units use a forced air blower, rather than a fan, because a blower incorporates a blower housing which isolates the blower motor from the hot gases produced in the combustion chamber. These latter style heaters have more specialized applications where such items as flame containment, low noise and/or better heat distribution are important. The development goal for such heaters is to optimize size, performance and cost. For example, a known heater of this type is manufactured by the National-Riverside Company, a Division of Scheu Products Company, Incorporated of Rancho Cucamonga, Calif., the assignee of the subject application, as their model 60FA-BE forced air propane gas portable heater. In this connection, the purpose of this invention is to provide an improved small forced air gas heater of this type which is lower in cost, easier to service, simpler in construction, and which provides more efficient cleaner combustion and more uniform circulation of heated air within the combustion chamber.